Association of interleg difference of ankle brachial index with overall and cardiovascular mortality in chronic hemodialysis patients

Abstract

Background: The ankle-brachial index (ABI) is associated with peripheral vascular atherosclerosis, adverse cardiovascular outcomes, and all-cause mortality. However, there were limited data available on studying the effect of interleg ABI difference.

Methods: We investigated the association of the interleg ABI difference with overall and cardiovascular mortality in chronic hemodialysis in a retrospective observational cohort of 369 Taiwanese patients undergoing chronic hemodialysis.

Results: An interleg ABI difference of ≥0.15 in hemodialysis patients had significant predictive power for all-cause and cardiovascular mortality in crude analysis. The hazard ratio (HR) for all-cause mortality was 3.00 [95% confidence interval (CI), 1.91-4.71]; the HR for cardiovascular mortality was 3.13 (95% CI, 1.82-5.38). After adjustment for confounding variables, this difference continued to have significant predictive power for all-cause mortality but lost its predictive power for fatal cardiac outcome. ABI <0.9 and high brachial-ankle pulse wave velocity were independently associated with an interleg ABI difference of ≥0.15 in hemodialysis patients. Moreover, in the subgroup analysis, we found that this difference was an independent factor for overall and cardiovascular mortality, particularly in elder patients, female patients, or those with ABI <0.9.

Conclusion: Detection of an interleg ABI difference of ≥0.15 was an independent risk factor for overall mortality in hemodialysis patients but it may affect cardiovascular mortality through the effect of peripheral vascular disease.

Keywords: All-cause mortality; ankle-brachial index; cardiovascular mortality; hemodialysis; peripheral vascular disease.